The present invention relates to a device for controlling an internal combustion engine.
German Patent Application No. DE-OS 40 409 27 describes a device for controlling an internal combustion engine which stores errors in a control device of a motor vehicle. If the control device recognizes an error, the instantaneous operating conditions are stored.
A device for controlling an internal combustion engine is described in German Patent Application No. DE 198 49 328. In response to the occurrence of an error, at least one value of a quantity is stored in a fault memory. At the least, the value of that quantity, which existed at a point in time prior to the occurrence of the error, is stored in the fault memory.
Both devices utilize the occurrence of an error as a criterion which prompts the quantities to be stored. No mention is made of considering another criterion.
A control system having data storage is described in German Patent Application No. 195 46 815. The control system is an engine-control unit, which contains a memory unit. Stored in this memory unit are data, which are supplied to the engine-control unit as data originating from the sensory mechanism allocated to the unit. Moreover, various data are supplied from a brake-slip control contained in the vehicle to the memory unit located in the engine-control unit. In response to a crash sensor detecting the occurrence of an accident, the data stored in a previous time period are permanently stored.
An object of the present invention is to provide a device for controlling an internal combustion engine where data or quantities are also stored in response to other events, such as errors or accidents. In this context, data or quantities are stored in response to an improper vehicle operation.
According to the present invention, a device for controlling an internal combustion engine is provided which includes a storage device in which data or quantities, existing in each case at earlier points in time, are continually stored. When a predefined condition is met, these data or quantities are successively overwritten, in each case, by data or quantities existing, in each case, at later points in time. In response to the occurrence of a predefined event, the data or quantities stored in the storage device, are permanently stored.
In accordance with the present invention, the predefined event is an improper operation of the vehicle.
Improper operation, in the sense of the present invention, is understood as follows:
By actuating the accelerator, the brake pedal, and the steering wheel, the driver adjusts the vehicle""s driving condition. This driving condition is defined by various parameters and/or quantities. Cited here, by way of example, are engine speed, vehicular speed or transversal dynamic quantities.
As long as the parameters, derived from actuation of the accelerator, the brake pedal, or the steering wheel, such as engine speed or vehicle deceleration, are within predefined limits; or, as long as these parameters are plausible, in view of certain marginal conditions, then there is proper operation of the vehicle.
On the other hand, there is improper operation of the vehicle when the resulting parameters are no longer within predefined limits, or exceed or fall below predefined limits. This is the case, for example, when the engine speed exceeds a predefined value. One can distinguish here between a shorter or longer period of time, the latter case being the more serious one.
Another case is when the internal combustion engine is operated in spite of an empty or substantially empty tank. This situation can be determined on the basis of a quantity describing the filling level of the tank, or on the basis of a quantity describing the residual amount of fuel in the tank.
Another case of improper operationxe2x80x94the parameters are implausible in view of certain marginal conditionsxe2x80x94exists, for example, in the following situations:
The internal combustion engine is operated at high speeds in a cold state. In spite of the fact that fault situations are indicated, for example by trouble localizer lights or acoustic signals, vehicle operation continues. This is the case, for example, when indicators warn of too high of an engine temperature, too low of an oil pressure, or of an error or defect in the braking system.
The use of program memory modules, e.g., E-PROMS, which permit a modified operation of the internal combustion engine, can also be detected. This manipulation, known as chip tuning, can potentially result in lasting damage to the vehicle""s transmission, since the transmission is loaded with a torque greater than that which is maximally allowed. In this case, the predefined event does exist, for example, when engine parameters lie above predefined values, which represent maximum values.
Along the lines of the present invention, an accident or an accident event is not to be understood as improper operation.
In response to improper operation of the vehicle, data or quantities are permanently stored, enabling them to be used in a potential later warranty claim.
Improper operation is advantageously recognized when the engine speed falls below a predefined value, for a predefined period of time. In such an operating state, there is the possibility that the internal combustion engine is affected. For that reason, it is important that such operating states be registered in the case of damage, in view of a potential warranty claim. Alternatively or additionally, improper operation is recognized, when it is ascertained that the internal combustion is being operated in spite of an empty or substantially empty tank. Furthermore, an operating state can also exist where combustion misses occur due to a defect. Typically, a flashing trouble localizer light signals this to the driver. Operating states of this kind can also affect the catalytic converter. In this connection, reference is made to German Patent Application DE 196 49 484 which describes this problem and a method for detecting disturbances caused by an empty tank in the case of an internal combustion engine. The entire disclosure of German DE 196 49 484 is expressly incorporated herein by reference.
A second predefined event, in this context, an accident, is also advantageously considered. In addition, permanently storing the data or quantities in response to the occurrence of an accident makes it possible to reconstruct the accident event afterwards and, possibly, clear up any unsettled question of guilt. An accident is advantageously recognized when an occupant-restraint system contained in the vehicle is triggered, and/or when the longitudinal acceleration, and/or the transversal acceleration of the vehicle is greater than predefined threshold values. The occupant-restraint system is advantageously an airbag system.
The predefined condition is advantageously met when all or a percentage of the storage device""s memory space is occupied. As can be easily recognized, this condition depends, on the one hand, on the memory space that the storage device makes available, or on the volume of data to be stored at any one time. When all of the memory space is occupied, data or quantities can no longer be stored after a predefined event occurs. On the other hand, the other condition, which is then met when a certain percentage of the memory space is occupied, has the decisive advantage that data or quantities can always still be stored after the predefined event occurs, due to the still available memory space.
The data or quantities stored in the storage device are advantageously input quantities, which are supplied to the device, or quantities, which are determined in the device within the context of internal combustion engine control. The data or quantities include, for example, vehicular speed, and/or wheel speeds, and/or engine speed, and or a load signal, and/or quantities describing a brake actuation, and/or the time of day, and/or the vehicle""s location, given the presence of a vehicle navigation system. It is also possible, however, to likewise store diagnostic and adaptation parameters describing the status of a vehicle component. Thus, for example, the catalytic converter status, ordinarily determined in an engine management system, can be stored as well. This enables one to clearly verify damage caused, for example, from driving with a nearly empty tank. In addition, in this connection, it is advantageous to record excerpts from the fault memory, i.e., recognized errors, such as diagnostic and/or adaptation parameters, which produce signals or quantities indicating, for example, the duration of use of individual components, or the wear they are subject to, or indicating whether the sensory mechanism or other components are functioning correctly, i.e.. are not impaired in their functioning.
The storage device is advantageously a ring-type memory, i.e., the storage device is designed or organized as a ring-type memory, i.e., is addressed accordingly. The advantage of a ring-type memory is that the data or quantities are stored in it on a circulating basis. In other words, as long as the memory is not yet completely written, for example, data or quantities continue to be stored in it. As soon as the memory is completely written, the data or quantities first stored in it are overwritten by the most recent data or quantities. In this procedure, the old data are successively replaced by newer data or quantities, with the oldest data or quantities always being replaced first.
The data or quantities contained in the storage device are advantageously transferred to an external evaluation device. Thus, the data or quantities stored in the storage device, can be analyzed, for example, at any time with little outlay.
It is especially beneficial when the storage device is an integrated memory module, in which data or quantities are able to be stored as volatile and non-volatile data. Here, it is a question, in particular, of an integrated semiconductor module. When an integrated memory module is used, it is easy and entails little outlay to integrate the storage device in the device to influence the first vehicle quantity.
The storage device is advantageously a component of a device for detecting errors or for monitoring functioning. As a result, a further benefit is derived from data or quantities produced in the memory device also being stored in this device.
Another benefit is derived from the storage device being contained in the device for controlling the internal combustion engine, i.e., from this storage device already being present or inserted in this device. This eliminates the need for installing a separate accident-data recorder later on. The result is substantially lower costs for the vehicle owner.
The non-volatile storing of data or quantities ensures that the data or quantities already contained in the storage device are no longer overwritten by the more recent data or quantities, i.e., the data or quantities already contained in the storage device are xe2x80x9cfrozenxe2x80x9d.
In comparison with the accident-data recorder described in German Patent Application No. 195 09 711, another advantage of the device in accordance with the present invention is that there is no need to accommodate a separate unit in the vehicle, since the function of storing data is integrated in the device for controlling the internal combustion engine. At the same time, this means that fewer costs accrue for the vehicle owner, since he or she has no need for a separate accident-data recorder.
The storage of the data or quantities is advantageously organized in such a way that a plurality of instances of improper operation are recorded, i.e., retained, without the first recorded data being overwritten, i.e., lost. In this manner, it can be determined over an extended period of time whether improper operation is occurring more often. For this purpose, once improper operation has occurred, a portion of the memory space of the storage device is blocked for the rolling-type storage of subsequent data or quantities, i.e., once improper operation exists, the rolling-type storage is implemented with the aid of a memory space that is reduced in volume.